1. Field of the Invention
The present invention relates generally to an optical fiber cable, and, more particularly, to a feedthrough enabling interconnecting two such cables through a wall, panel or a pipe having an internal panel, and which feedthrough is hermetically sealed to prevent access and passage of pressurized fluids (liquids or gases) therethrough.
2. Description of Related Art
Optical fibers which are used to transmit light signals from one point to another frequently are required to pass from one fluid pressure environment to a different fluid pressure environment and the two environments are separated by a wall or panel hereinafter merely referenced to as a panel. In this case, the fiber must pass through the wall or panel and be secured at the panel in a manner to produce hermetic sealing completely about the fiber as well as through the device used to mount it into the panel in order that the high pressure side fluid will not be able to pass through the panel and undesirably be added to the fluid contained on the low pressure side of the panel.
Also, although under some circumstances it may be possible to hermetically retain a whole unbroken fiber within an opening in the panel separating two different pressure environments, in the usual case, it is far more convenient to break the fiber or to connect two fibers via so-called termini which are, in turn, mounted to the panel. It is in this latter situation that the invention described herein is most advantageously employed.
Although there are a number of termini known and used at this time for effecting connections between the ends of a broken fiber or between two separate fibers, none are known that possess fully satisfactory hermetic sealing requirements along the fiber and through the terminus interior parts. For example, in U.S. Pat. No. 4,290,667 each fiber has its end portion received within a capillary tube with a faced off fiber end located at the focal point of a lens. A pair of such fiber and lens devices are located at opposite ends of an alignment sleeve to form a fiber connector having two termini. However, the arrangement is strictly accomplished by mere contact with the various terminus parts which would not prevent a pressurized fluid (e.g., air or gas) from passing through the interior of the termination device.
In addition, known termini are expensive and complex to manufacture and have as a most serious objection the fact that they are difficult to use in a practical context as well as being quite frequently not reliable in operation. Still further, highly trained personnel are frequently required for fabricating and utilizing the known devices since assembly of the devices must be accomplished in a manner to avoid even extremely small (microscopic) dust particles from becoming located between the fiber ends to be terminated, which particles could otherwise produce a substantial reduction in the fiber cable light transmission efficiency.